A Quantitative Reservoir Evaluation Method Based on Fuzzy Comprehensive Appraisal and Analytic Hierarchy Process

Abstract

The classification and evaluation of reservoir is not only critical part of reservoir study, but also the fundamental of reservoir description. Based on the interpretation ambiguity and mutual contradictions of the evaluation methods in the past, this paper proposes a new quantitative reservoir evaluation method that combines fuzzy comprehensive appraisal and analytic hierarchy process to conduct a quantitative reservoir evaluation. The combination of those two technologies takes advantages of only using either of them and applied to the case study of Xjiahe Zu Formation. The reservoir parameters, such as reservoir porosity (Φ), permeability (K), reservoir effect pay (H) and the ratio of sand thickness and stratum thickness, as well as clay content, are used to determine the functions and membership grade. Analytic hierarchy process (AHP) was applied to determine the weight indexes based on above parameters to evaluate the reservoir. The results show the calculated weight of reservoir porosity (Φ), permeability (K), reservoir effect pay (H) and the ratio of sand thickness and stratum thickness, clay content are 0.1948, 0.4052, 0.2034, 0.0981, 0.0985, respectively. The results match very well with the actual field data of Xujiahe Zu Formation, Baojie Area.